Novel Ir1–xCoxO2 thin films: growth and characterization

DOI: 10.1016/j.jallcom.2023.171975

Authors: M. A. Laguna-Marco (CSIC - Universidad de Zaragoza) , Julia Herrero-Albillos (CSIC - Universidad de Zaragoza) , M. H. Aguirre (CSIC - Universidad de Zaragoza) , M. Rueda-Jiménez (Universidad de Zaragoza) , I. Mikulska (Diamond Light Source)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Journal Of Alloys And Compounds , VOL 4

State: Published (Approved)
Published: September 2023
Diamond Proposal Number(s): 32410

Abstract: Ir1–xCoxO2 thin films have been prepared by reactive co–sputtering deposition at room temperature. Composition, structure, electronic properties and electric and magnetic behavior have been analyzed by different techniques including XRR, XRD, TEM microscopy, SQUID magnetometry, electrical resistivity and XAS spectroscopy. After annealing, an Ir1–xCoxO2 substitutional solid solution phase with rutile crystal structure was achieved for a wide Co-doping range 0 ≤ x ≤ 0.6. Starkly departing from the highly insulating behavior of CoO and Co3O4, the electrical resistivity at room temperature of our films is only slightly higher than that of IrO2. Likewise, our work shows that the magnetic response of the doped films is very similar to that of the paramagnetic parent IrO2. Neither ferromagnetism nor enhanced paramagnetism is observed. XAS spectra indicate a Co3+ oxidation state and, correspondingly, an oxidation state of ∼5+ for Ir ions in the polycrystalline Ir0.6Co0.4O2 film. By application of sum rules, a 13% increase in the spin–orbit coupling is found despite the lattice shrinkage causes a detrimental bandwidth broadening.

Subject Areas: Materials, Physics


Instruments: B18-Core EXAFS

Added On: 05/09/2023 09:03

Documents:
1-s2.0-S0925838823032784-main.pdf

Discipline Tags:

Surfaces Quantum Materials Hard condensed matter - electronic properties Physics Electronics Magnetism Materials Science interfaces and thin films

Technical Tags:

Spectroscopy X-ray Absorption Spectroscopy (XAS) Extended X-ray Absorption Fine Structure (EXAFS)